Mathematically, Lulu shouldn't be the only support going mid lane [ANALYSIS] [x-post from GD]
This post is a cross-post from GD. The original thread is here. I'm posting it up here because I'm having trouble keeping it bumped on GD and I wanted to get some real feedback on the theorycrafting I did here that isn't just "thank you for saying Lulu isn't OP".
The original post follows:
I was thinking about the sudden rise of Lulu mid, and I was confused originally on why people picked her. She certainly doesn't have significant burst, and there are other supports with more utility. It can't possibly just be Lulu in mid lane-what about the other supports?
So, last night, being a person who prefers to think about these sort of things, I ran some numbers from Lolwiki. I took the numerical values of each of the traditional supports (e.g: supports who were considered as such before S4 AND are not inherently bulky) and made them into two values: Offensive, Defensive, and Overall, plus a Subjective category.
Offensive: This number plus ratio evaluates the total sum of the damage a support can put out to an enemy champion in one spell rotation. I did allow Sona and Nami to proc their autoattack effects, but counted only their damage buffs and not their actual base attack damage. Can't really be debated, as I'm taking the scenario that most favors the champion in question.
Defensive: This number plus ratio evaluates the total sum of the damage a support can protect themselves or a teammate from in one spell rotation. All heals only apply single target. Not really debatable either, even if the scenario presented is unlikely to occur (soraka somehow only ever heals people who are at 1 HP lol).
Overall: This number represents the sum of the Offensive and Defensive totals.
Subjectives: This category is essentially where I'll talk about the champion and what they do in mid lane in comparison to the gold standard, Lulu. I call these Subjectives because unlike the sections above, these things can't be assigned numerical values and can be debated. Does Lulu having to choose whether to use her E for offense or defense make up sufficiently for getting an extra skill compared to Janna's similar numbers? I really can't say objectively.
So, without further delay, here's the objective measures:
All of these assume optimal ability use for whatever purpose you're using the ability for (for example, Nami will always pop all 3 of her E autoattacks and Janna will always full channel her ult).
Offensive/Defensive Output per Second are calculated by taking each skill's base value plus ratio, dividing it by the cooldown of the ability, and then adding up all the abilities.
Offense: 540 (+0.9 AP) Defense: 840 (+1.1 AP) Overall: 1380 (+2.0 AP) Offense per second: 166.66 (+0.28 AP) Defense per second: 31.5 (+0.06 AP) Overall per second: 198 (+0.34 AP)
Offense: 545 (+1.15 AP) Defense: 840 (+2.5 AP) Overall: 1385 (+3.65 AP) Offense per second: 55.38 (+0.11 AP) Defense per second: 29 (+0.08 AP) Overall per second: 84.38 (+0.19 AP)
Offense: 1130 (+2.2 AP) Defense: 185 (+0.3 AP) Overall: 1315 (+2.5 AP) Offense per second: 81.74 (+0.17 AP) Defense per second: 20.55 (+0.03 AP) Overall per second: 102.29 (+0.2 AP)
Offense: 984 (+1.4 AP) Defense: 100 (+0.25 AP) Overall: 1084 (+1.65 AP) Offense per second: 167.21 (+0.21 AP) Defense per second: 14.29 (+0.03 AP) Overall per second: 181.5 (+0.24 AP)
Offense: 360 (+0.8 AP)(+0.05 mana) Defense: 927 (+1.35 AP) Overall: 1287 (+2.15 AP)
Offense per second: 96 (+0.06 AP) Defense per second: 24.14 (+0.03 AP) Overall per second: 120.14 (+0.09 AP)
(sorry, the type of formatting I want doesn't translate well from GD. Take a look at the original formatting here: http://forums.na.leagueoflegends.com/board/showthread.php?t=4403652)
So, with all that in mind, let's go to the subjectives:

Even though she has some of the lowest individual values (landing in 4th place in offense and tied for 2nd place on defense), she's the most popular of the above picks, for a number of reasons. She's not really that great when fed because of her meh ratios; instead, you'd pick her mid lane because she's SO DAMN GOOD at making other fed players shine. Her massive slows on Glitterlance plus knockup on Wild Growth are just godly for making the bruiser of your choice inescapable or your marksman unkillable. The real X factor, though, is her Whimsy. It's effectively a 2 second stun, which is something nobody else on the list brings.
Lulu's got great sustained damage thanks to her passive and great synergy with just about every teamcomp; my only qualm with her is that her E is a big part of both her offenses and defenses and it can't be used for both at once. Unlike, say, Janna, who can shield+ult and still have Howling Gale+Zephyr left, Lulu has to choose between offense and defense, making her less flexible in situations where it's not immediately clear which one you need. Really, though, that's a small nitpick compared to her number of strengths, which is probably why LCS teams picked up her instead of any of the other supports with passable numbers.

Honestly, if Lulu gets nerfed again Janna would probably take her place.
No seriously.
Look at Lulu and Janna's values. Lulu and Janna mathematically have almost the same offensive and defensive values, but Janna has much higher ratios and the ability to heal in an AoE (which wasn't accounted for in said numbers). Given the channels on Howling Gale and Monsoon, it's not enough to give her a niche over Lulu at the moment...but expect to see her in pro play if Lulu gets nerfed. While Janna's ratios are massive (the highest on the list by far), there are two things that really hold her back in mid lane at the moment; mana costs and cooldowns. Howling Gale has a 14->10 second cooldown and costs 150 mana (!) when maxed; Monsoon's cooldown is 150 seconds, though its mana cost is thankfully normalized at 100.
That being said, Janna's defensive utility is through the roof. At level 1, her passive plus a point in W essentially give you free boots. With the right items you can put off investing in boots for much longer then the other supports, helping you to get ahead in items. Howling Gale is an amazing self-peeling spell that pretty much makes Janna ungankable, but also can act as a long range poke spell. You'd be surprised at how many people just can't dodge the tornado even when they have 3 seconds' warning. Her ult is essentially a teamfight reset; she kicks out the enemy team and heals everyone standing reasonably close to her for up to 600 (+1.8 AP); late game, that can be over 1400 HP!

Nami hits HARD. Her total offensive burst value is 1130 (+2.2 AP) not including the autoattacks necessary to hit E three times. For reference, Lux hits for 1190 (+2.05 AP) assuming one passive proc.
Her ability to compete with many standard AP mids in terms of early game burst is extremely attractive, but what really sets her apart from the crowd is her W, which wins an awful lot of trades with one button press. At level 9, you're dishing out 230 (+0.5 AP) damage to the opponent and then returning 148 (+0.26 AP) HP to yourself-effectively a 378 (+0.76 AP) damage swing in one button press. This gets even crazier when you realize that the -15% modifier on each bounce after the initial cast can be negated with 200 AP and reversed (so that subsequent bounces deal MORE DAMAGE or HEAL MORE then the original cast).
However, she falls victim to one of the normal support problems in mid lane: long cooldowns. The only ability she gets at a less then 10 second cooldown at any level is W, which also doesn't scale and stays flat at 9 seconds. This combined with her low natural movement speed and iffy self-peel (Q is inconsistent even when someone's diving you and E can't be used effectively on defense with Nami's terrible AA animation) make it difficult to escape ganks like Janna or Lulu can.

The regular measurements that aren't weighted with cooldowns don't really treat Sona fairly. A lot of her power is tied up in intangibles; it's hard to judge exactly how much her auras are giving you at any given moment. That being said, she is notable for having great cooldowns (her regular abilities have 7 at all levels and her per second values are almost as strong as Lulu's), allowing her to be a sustained threat in conjunction with power chord. She also has excellent item synergy, being one of the best users of Archangels' Staff and Lich Bane.
Of course, with all those upsides, you must be waiting for the other shoe to drop. Sona is ONE OF THE SQUISHIEST CHAMPIONS IN THE GAME AT ALL LEVELS, especially against physical damage. You better hope you're not against a Talon or Zed, or you're gonna get dunked. It doesn't help that she also has no escape other then her E, which is a hilariously bad skill until late late game. She CAN work thanks to her massive AoE stun on her ulti and her strong damage and item synergy, but you really have to play carefully in order to get there.

Another champion that the measurements don't do justice. Soraka's damage is better then it appears and her damage is deceptively strong in an extended fight. She also brings a big armor buff and unique mana restoration skill, which gives her a decent niche against AD casters.
You don't pick Soraka for her laning, really. You pick her because she's the best burst healer in the game and she's practically built for lasting through a long fight. Her Q synergizes wonderfully with Archangels', Rylai's, Lich Bane...you name it. W has a long cooldown but is well worth the wait with the massive buff. Finally, her ult tops off her kit with a massive team-wide heal that doesn't require a long channel like Janna's.
That being said, Soraka still has issues. She's very vulnerable to ganks because all she has to protect herself is heals and the one measly silence. She can have mana issues early on, especially since her main DPS source is Q. Finally, she doesn't burst, really. At all. Your only option is a sustained fight, so if you run up against someone who can kill you in one combo you might as well step away from the keyboard before the game even starts.
Conclusion
Please keep in mind while posting that these picks are MEANT to represent a tradeoff to the usual assassin/burst mage crowd in mid lane. With the exception of Nami and maybe Sona, they don't deal the damage that most mid laners do; instead, you pick them for their extreme utility and make up the damage in top lane or jungle.
There are other supports that can mid lane out there then Lulu. Janna and Nami both have incredible team support utility with different strengths' than her. Soraka and Sona are almost there and can be great in the right matchups. Get out there and play them in Team Builder, normals, whatever. Get comfortable with them. They DO work, they CAN compete, and the damage you lose is easily made up by other members of the team.